The present invention relates to automatically controlled cutting machines that are used to cut limp sheet material, such as woven and nonwoven cloth, paper, leather, synthetics, composite materials, and others.
Reciprocated cutting blades in automatically controlled cloth cutting equipment are well known in the art and are shown in U.S. Pat. No. 3,495,492 and others. The cutting blade is typically a thin elongated blade having a sharp leading cutting edge that is advanced through the sheet material on a predefined line of cut while the blade is simultaneously reciprocated in a direction generally perpendicular to the material.
More recently, it has been recognized that cutting of limp sheet material can be performed with the aid of ultrasonic vibrations. U.S. Pat. No. 4,373,412 issued to Gerber and Pearl discloses a cutting machine in which a cutting wheel having a sharp peripheral cutting edge is vibrated ultrasonically as the wheel rolls across a hard cutting surface on which the sheet material is positioned for cutting. The ultrasonic vibrations are believed to assist in the cutting operation by crushing the material between the cutting edge and the support surface. U.S. Pat. No. 3,378,429 issued to Obeda also discloses an ultrasonically activated tool to slit and seal textile materials made of synthetic fibers.
The prior art cutting tools mentioned above vibrate a cutting edge toward and away from a support surface on which the sheet material is positioned or moved to accomplish the cutting operation. However, in the manufacture of clothing, upholstery, and other items at large scale, the sheet material is generally cut in multi-ply layups, and the concept of using a support surface as an anvil in conjunction with an ultrasonically vibrated cutting tool cannot be employed.
It is accordingly a general object of the present invention to provide an automatically controlled cutting apparatus and method in which multi-ply layups of sheet material can be cut with the aid of ultrasonics. It is a further object of the invention to provide apparatus and method for drilling through multi-ply layups of sheet material with the aid of ultrasonics.